a. Field of the Invention
This invention relates to an activated carbon, and more particularly to an activated carbon made from macadamia nuts.
b. Prior Arts
Activated carbon is widely used, for example, for removal of impurities, capture or recovery of specific components, separation of mixtures, or the like, by utilizing its remarkable adsorptivity, and the demand for the activated carbon has been increased year by year. In fact, the demand has exceeded the supply for these years. Especially, activated carbon of good quality is in serious shortage.
Heretofore, the activated carbon is made of coconut shell, vegetable coal, sawdust, wood chip, or the like. Recently, it has been proposed to use pulp waste as a raw material of the activated carbon (Japanese Patent Application Laid-Open Specification No. 48-20793).
The activated carbon is produced from these materials through carbonization and activation processes after some preliminary treatment or without such pretreatment.
The properties of the activated carbons are determined by the qualities of the materials employed as well as the activation conditions. Therefore, good quality materials are sought for.
c. Problems to Be Solved by the Invention
The most outstanding problem in the production of the activated carbon is acquirement of the materials. While good-quality materials are needed as described above, the good-quality materials such as coconut shell are produced only at local areas on the world and the increase of the production can not be expected easily. This makes the material supply unsteady and the material price increased.
The second task is to prepare activated carbon of high regeration efficiency. The used activated carbon is regenerated for re-use to substantially reduce the cost of the activated carbon. For this reason, it is needed to produce activated carbon of little ash content and having a high regeneration efficiency. Such activated carbon can hardly be obtained from such materials as saw dusts or wood chips but only obtained from the good-quality materials such as coconut shells. However, there is again a problem that the supply of such good-quality materials are limited.
The third task is to reduce the cost of the activated carbon. As described above, the cost of the activated carbon has recently been raised due to the rising cost of the materials. For this reason, the possibility of the use of cheaper materials has been discussed. The materials such as saw dusts, wood chips or pulp wastes are advantageously cheap in cost, but they have such a problem that the quality of the activated carbon obtained from these materials is rather poor. In addition, in case of the pulp wastes, complicated pretreatment is needed, which raises the manufacturing cost. Thus, it is very difficult to economically obtain activated carbon of good quality.